WHAT TO WATCH: Primaries test GOP, Democratic identities

Democrats hope to grab a House seat that Republicans have held for decades. A tweet from President Donald Trump could tip a GOP gubernatorial primary in Kansas. Democrats continue to decide how far to the left the party should move. And critical Senate races are coming into focus.

What to watch as voters in five states head to the polls Tuesday:

BATTLEGROUND OHIO

Ohio's 12th Congressional District doesn't normally get this much attention.

But a special election to fill a seat vacated by a longtime Republican congressman is becoming a barometer of where the midterms may be heading. Danny O'Connor, a 31-year-old local election official, appears to be within striking distance of becoming the first Democrat to represent this stretch of central Ohio in decades.

An O'Connor victory would be another strong sign of Democratic enthusiasm as the party pushes to take back control of the House in November. In fact, given how poorly they've fared here in the past, Democrats would likely be encouraged even if they lose by a few percentage points.

O'Connor is facing Republican Troy Balderson, a 57-year-old state senator endorsed by President Donald Trump.

The district reaches from parts of liberal-leaning Franklin County, home to Columbus and The Ohio State University, through suburbs and into small-town Ohio. Trump won there by more than 11 percentage points in 2016 and has pulled out all the stops to keep it in the GOP column, including holding a rally with Balderson over the weekend.

For all the attention — and cash — the race is receiving, the special election is about more than a single House seat up for grabs in a competitive midterm election year. The results could signal where Ohio is trending heading into the next presidential election.

A strong showing by O'Connor would give Democrats hope that they could regain ground they lost in 2016 when Trump dominated the state. A big Balderson victory, however, could help soothe GOP anxiety that Trump's grip on the Midwest could be waning.

TRUMP EFFECT

If Trump's endorsement doesn't carry his preferred candidate across the finish line in Ohio, he'll look to Kansas, where he backed Secretary of State Kris Kobach's bid to become governor.

Kobach is a hard-line conservative who shares the president's views on immigration and echoes his unproven assertions about voter fraud in U.S. elections. He's in a tight race against incumbent Republican Gov. Jeff Colyer and insurance commissioner Ken Selzer among others.

Trump named Kobach to help lead a post-2016 election commission aimed at uncovering voter fraud. The group disbanded this year after finding no evidence of fraud in the presidential election as Trump had claimed after losing the popular vote.

Kobach also is a staunch anti-tax conservative who promises to continue former Gov. Sam Brownback's approach of sweeping tax cuts after his election in 2010. They became unpopular when promises of economic growth didn't materialize but cuts to schools and other public services did.

Colyer, who stepped in for Brownback after Trump named him to an ambassadorship, hails from the more moderate branch of the Kansas GOP that has rolled back some of Brownback's fiscal moves. An incumbent Kansas governor has lost a primary only twice since the state began holding such elections 110 years ago, the last time in 1956.

If Kobach comes out on top, Democrats believe they have an unusual shot at making the general election competitive. But their hopes could be complicated by Greg Orman, a Kansas City-area businessman who submitted petitions Monday with more than 10,000 signatures for what could become the most serious independent run for Kansas governor in decades. If he gets on the ballot and gains tractions, it could come at the expense of Democrats.

DEMOCRATIC IDENTITY BATTLES

Tuesday's primaries will give Democrats another opportunity to work through internal divides between progressives and more mainstream liberals and moderates.

An eastern Kansas district anchored in Kansas City will decide whether to nominate labor lawyer Brent Welder, a former presidential campaign aide to Vermont Sen. Bernie Sanders, to face Rep. Kevin Yoder in a district that narrowly opted for Hillary Clinton in 2016.

Welder campaigned with Sanders and Alexandria Ocasio-Cortez, the democratic socialist who ousted a top Democratic House leader in a New York City primary in June.

In a suburban Detroit district, three mainstream Democrats are viewed as leaders to vie for a GOP-held seat in November: former legislator Tim Greimel, endorsed by Sen. Carl Levin; Suneel Gupta, a tech executive and entrepreneur and younger brother of Dr. Sanjay Gupta of CNN; and Haley Stevens, who ran the Obama administration's auto bailout program.

In the outside lane is Fayrouz Saad, who'd be the first Muslim woman in Congress. She doesn't have Welder's momentum, but she backs single-payer health insurance and other progressive policy ideas, and hopes that her better-funded rivals split most of the votes, allowing her to squeeze through.

In suburban Seattle, three Democrats are vying in a jungle primary for the seat held by Rep. Dave Reichert, who is retiring. That likely means that just one of pediatrician Kim Schrier, attorney Jason Rittereiser, and former federal public-health official Shannon Hader will advance along with Republican state Sen. Dino Rossi.

The Democratic Congressional Campaign Committee hasn't taken sides in those races, but national Democrats say they are bullish on all three seats regardless of Tuesday's outcome.

FALL RACES COME INTO FOCUS

Two critical races that could determine which party controls the Senate will come into focus Tuesday. Missouri's Claire McCaskill began the cycle presumed to be the most vulnerable Democratic incumbent. Since then, she's smoked her top Republican rival, Attorney General Josh Hawley, in fundraising, but also endured bad headlines about her use of a private jet. Tuesday's election will serve as a measure of enthusiasm for both candidates.

In Michigan, Sen. Debbie Stabenow joins McCaskill among the 10 Senate Democrats facing re-election in states Trump won. Polls suggest she's in a strong position as she awaits her GOP opponent. Among the possibilities: military veteran and business executive John James, who'd join Tim Scott as the second black Republican in the Senate.

Kansas Secretary of State Kris Kobach speaks during a press conference in Mission, Kans., after President Donald Trump officially endorsed him for Kansas governor on Monday, Aug. 6, 2018, ahead of the Tuesday primary. (Shelly Yang/The Kansas City Star via AP)

In a Friday, July 31, 2018 photo, Kansas Governor Jeff Colyer arrives with his family to advance vote at Hilltop Learning Center in Overland Park, Kansas. (John Sleezer/The Kansas City Star via AP)

Republican Troy Balderson, a candidate for Ohio's 12th District, joins volunteers at a phone bank in Westerville, Ohio, on Monday, Aug. 6, 2018, a day ahead of a special election for the congressional seat. Balderson, a two-term Republican state senator, is working to retain GOP control of the 12th District. He faces Democrat Danny O'Connor, the Franklin County recorder, whose fundraising outpaced Balderson's during the most recent reporting period by nearly four times. (AP Photo/Julie Carr Smyth)

Kansas City-area businessman Greg Orman, center, and Sen. John Doll, right, deliver more than 10,000 signatures to the Secretary of State's office in Topeka, Kan., Monday, Aug. 6, 2018, to formalize their campaign for governor. He needs the signatures of 5,000 registered voters to appear on the November ballot. (Thad Allton/The Topeka Capital-Journal via AP)

Heather Heine of Ferndale holds a sign that reads "Let's grab them by the midterms" at a Get Out The Vote rally for Michigan Democratic gubernatorial candidate Abdul El-Sayed at Cobo Center in Detroit on Sunday, Aug. 5, 2018. (Jacob Hamilton/Ann Arbor News via AP)

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